1. Field of the Invention
The present invention relates to a heat exchanger. More particularly, the present invention relates to a heat exchanger which collects exhaust heat of high temperature so as to warm up an engine and to heat a cabin and a battery and reduces noise of an exhaust gas.
2. Description of the Related Art
Generally, a heat exchanger makes an exhaust gas exchange heat with a coolant so as to lower temperature of the exhaust gas of high temperature and to raise temperature of the coolant of low temperature. The coolant heated by such a heat exchanger is used for warming up an engine quickly (fast warm-up) when temperature of the engine is low or heating a cabin or a battery.
A conventional heat exchanger includes an exhaust pathway though which the exhaust gas passes, a coolant pathway through which the coolant passes, and a bypass pathway bypassing the exhaust gas according to an operating condition of the engine. In a case that the engine operates with low speed, the exhaust gas passes through the exhaust pathway. On the contrary, in a case that the engine operates with high speed, the exhaust gas passes through the bypass pathway. The bypass pathway is disposed closer to the coolant pathway than the exhaust pathway. Therefore, the exhaust gas of high temperature is cooled by the coolant when passing through the bypass pathway, and the exhaust gas of low temperature is cooled by the coolant when passing through the exhaust pathway.
In order to install a conventional heat exchanger to a vehicle, an auxiliary muffler disposed at a lower end of a center floor in the vehicle should be removed. A conventional heat exchanger should be mounted at a position where the auxiliary muffler was mounted. As the auxiliary muffler is removed, noise of the exhaust gas may increase. Since the noise of the exhaust gas increases, inner noise and outer noise also increase and it may hard to meet noise regulations.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.